Phytonutritional Content and Aroma Profile Changes During Postharvest Storage of Edible Flowers

Abstract

Edible flowers are niche horticultural products, routinely used as cooking ingredients in the food industry. Currently, new species are required with the aim of enlarging the number of species with a long shelf-life, healthy nutraceutical compounds, and new fragrance and tastes. Ageratum houstonianum Mill, Tagetes lemmonii A. Gray, Salvia dorisiana Standl, and Pelargonium odoratissimum (L.) L’Hér “Lemon” were selected for their different morphological characteristics and color. Fresh flowers were analyzed to characterize their phytonutritional content and aroma profile. Postharvest was determined up to 6 days of cold storage at 4°C in transparent polypropylene boxes. Visual quality and cellular membrane damage were observed. The relative content of different antioxidant constituents (e.g., polyphenols, flavonoids, anthocyanins, ascorbic acid), nutritional compounds (soluble sugars, crude proteins), the antioxidant scavenging activity, and the volatile profile were determined and correlated to the quality of shelf-life of the different species. The yellow T. lemmonii freshly picked flowers showed the highest ascorbic acid and flavonoids content, which was maintained during the cold storage, as well as the best visual quality. Limited changes in metabolites were detected in the light blue A. houstonianum during postharvest, although the visual quality is severely compromised. Magenta S. dorisiana and light pink P. odoratissimum showed similar changes in antioxidant constituents during cold storage. For the first time, the volatile compounds have been identified in the four species. Sesquiterpene hydrocarbons are the main class in fresh flowers of A. houstonianum, S. dorisiana, and P. odoratissimum, while monoterpene hydrocarbons are abundant in T. lemmonii. The cold storage influenced mainly P. odoratissimum and S. dorisiana flavor initially dominated by the increase in total monoterpenes at 6 days, reaching a relative content of 90%. Both A. houstonianum and T. lemmonii conserved the prevalence of the same class of constituents in all the analyzed conditions, even though the cold storage influenced the major compound abundance. On the basis of the results, T. lemmonii was the most interesting species with the longest shelf-life due to its phytonutritional and aromatic constituents. Results indicated the peculiar metabolic and physiological attitude of flowers species to cold storage.

Phytochemicals and Volatiles in Developing Pelargonium ‘Endsleigh’ Flowers

“…A relatively low number of compounds have been detected in extracts obtained from the floral tissues of P. 'Endsleigh' flowers; we have identified approximately the same number of flavonoids as Boukhris et al [28] in leaves and flowers of P. graveolens, but far fewer than the 40 compounds found by Marchioni et al [29] in Pelargonium odoratissimum 'Lemon' or of over 50 compounds identified in the flowers of P. endliclerianum [30]. Few metabolites are in common with the flower of Geranium sylvaticum [22] but those shared kaempferol, quercetin and myricetin methyl ethers, are known to function as defensive compounds against herbivorous insects [31].…”

“…The level of total phenolic compounds was significant; the reported values are similar to those of flowers of P. odoratissimum [29] in which TPC content was the highest among the flowers of the four species analysed, and approximately 40% and 50% higher than that one of the flowers of Geranium sylvaticum [32] and P. graveolens flowers [28], respectively. Comparing with literature regarding edible flowers, the TPC content results 50% higher than the best of the 26 flowers analysed by Demasi et al [33] and within the range of values reported by Janarny et al [34] for Sri Lankan edible flowers.…”

“…There is very little work on the volatile compounds emitted by Geraniaceae flowers, hence it is only possible to compare data with Bozan et al [30] (P. endliclerianum), Cao et al [35] (P. hortorum), and Marchioni et al [29] (P. odoratissimum). The major volatiles of P. endliclerianum flowers were Germacrene D (27.11%), β-Caryophyllene (11.34%), α-Phellandrene (9.79%), α-Pinene (4.89%) [30]; for P. hortorum Zingiberene (29.88%), α-Longipinene (26.65%), β-Myrcene (11.07%) and 3-Hexen-1-ol (5.39%) [35]; for the P. odoratissimum the two most present compounds were again Germacrene D (27.03%) and β-Caryophyllene (23.23%), followed in order by (E)-β-Farnesene (9.63%) and α-Humulene (5.21%) [29]. Table 5 shows instead the main volatiles of the P. 'Endsleigh' flowers at full bloom are different: the two major compounds are Guaia-6-9 diene (54.99%), and 3-Carene (11.25%), followed by β-Caryophyllene (5.49%) and Cadina-1(10),4-diene (4.70%), with Germacrene D only at 1.43%.…”

Crop Yield and Essential Oil Composition of Two Thymus vulgaris Chemotypes along Three Years of Organic Cultivation in a Hilly Area of Central Italy

“…Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were performed as reported in a previous study [43]. Briefly, a matrix of correlation was used for the measure of eigenvalues and eigenvectors in PCA analysis where the plot was performed selecting the two highest principal components (PCs).…”

Preservation of color and nutrients in anthocyanin‐rich edible flowers: Progress of new extraction and processing techniques

“…Nowadays, cold storage is a common nontoxic treatment for prolonging the shelf life of flowers. This treatment first affects the visual quality of flowers, and hydration is an important feature in maintaining the shape of flowers once they are bloomed Marchioni et al (2020). investigated the cold storage of four edible flowers (Ageratum houstonianum, Tagetes lemmonii, Salvia dorisiana, and Pelargonium odoratissimum) for 0-6 days.…”